Flat panel displays have been widely used in various products and fields in recent years, and the flat panel displays are required to have a larger size, a higher definition, and lower power consumption.
In this situation, organic EL devices, which include organic EL elements utilizing electroluminescence of organic materials, draw great attention as display devices for flat panel displays that are of solid state and are excellent in terms of low-voltage driving, rapid response, and self-luminousness.
The organic EL devices each include, for example, thin film transistors (TFTs) and organic EL elements connected to the TFTs on a substrate such as a glass substrate. The organic EL elements each have a stacked structure of a first electrode, an organic electroluminescence layer (hereinafter, also referred to as an organic EL layer), and a second electrode in the given order. The first electrode is connected to the corresponding TFT. The organic EL layer has a stacked structure of a hole-injection layer, a hole-transport layer, an electron-blocking layer, a light-emitting layer, a hole-blocking layer, an electron-transport layer, an electron-injection layer, and other layers.
Full-color organic EL devices generally have organic EL elements of three colors, i.e., red (R), green (G), and blue (B), as sub-pixels. These sub-pixels are arranged in a matrix, and three sub-pixels of the respective colors constitute one pixel. Then, these organic EL elements are selectively made to emit light at desired luminances, so that the display device shows an image.
In production of such an organic EL device, a pattern of the light-emitting layer is formed from a light-emitting material correspondingly to the organic EL elements (sub-pixels) of the respective colors.
Proposed examples of methods of forming a pattern of the light-emitting layer include vapor deposition with the substrate being in contact with a vapor deposition mask having a size similar to the substrate (hereinafter, also referred to as contact film formation); and vapor deposition on the whole substrate using a vapor deposition mask smaller than the substrate with the substrate being transferred (scanned) relative to the vapor deposition mask and a vapor deposition source (hereinafter, also referred to as scanning film formation) (for example, see Patent Literature 1).
Examples of vapor deposition devices to be used in formation of the organic EL layer include the following.
Patent Literature 2 discloses a film-forming device for forming a film on a substrate, including a first film-forming mechanism for forming a first layer and a second film-forming mechanism for forming a second layer inside a treatment container.
Patent Literature 3 discloses a vacuum film-forming device including a film-forming chamber configured to be in vacuo, a vapor deposition source disposed opposite to a substrate to be treated in the film-forming chamber, a gas inlet configured to introduce gas into the film-forming chamber, and a vent configured to discharge gas from the film-forming chamber, wherein the vent is positioned on a virtual line extended from the gas inlet in the gas-introducing direction and the virtual extended line crosses the central portion of a vapor deposition material stream from the vapor deposition source to the substrate to be treated.
Patent Literature 4 discloses a reduced-pressure vapor deposition device including a vapor deposition dish in a chamber, wherein, in formation of a vapor-deposited film, the atmospheric pressure for forming a vapor-deposited film is made to a gas pressure of the molecular flow region, and in at least a certain period of non-formation of a vapor-deposited film, the atmospheric pressure is made to a gas pressure of the viscous flow region.